ActionToolBar in KCM is broken in Qt6
Several KCMs, e.g. colors, icons, cursor, style, have Kirigami.ActionToolBar in a footer.
In Qt6 this results in the footer being not visible.
There's warnings like
kf.kirigami: Failed to find a Kirigami platform plugin
kf.kirigami: Could not create delegate for ToolBarLayout
kf.kirigami: file:///home/nico/kde6/usr/lib64/qml/org/kde/kirigami.2/ActionToolBar.qml: Maximum call stack size exceeded.
kf.kirigami: Could not create delegate for ToolBarLayout
kf.kirigami: file:///home/nico/kde6/usr/lib64/qml/org/kde/kirigami.2/ActionToolBar.qml: Maximum call stack size exceeded.
kf.kirigami: Could not create delegate for ToolBarLayout
kf.kirigami: file:///home/nico/kde6/usr/lib64/qml/org/kde/kirigami.2/ActionToolBar.qml: Maximum call stack size exceeded.
kf.kirigami: Could not create delegate for ToolBarLayout
kf.kirigami: file:///home/nico/kde6/usr/lib64/qml/org/kde/kirigami.2/ActionToolBar.qml: Maximum call stack size exceeded.
kf.kirigami: Could not create delegate for ToolBarLayout
kf.kirigami: file:///home/nico/kde6/usr/lib64/qml/org/kde/kirigami.2/ActionToolBar.qml: Maximum call stack size exceeded.